However, when asked to officiate at the union of his son and another man a week ago, Bardet did not hesitate.

“It seemed perfectly normal for me to carry out the marriage even though I still don’t agree with gay marriage,” Bardet, 72, told his local newspaper Le Dauphiné Libéré.

“When my son asked me if I’d do it, I immediately told him ‘yes’, because I did the same for his sister and because we get on well. I didn’t want to give the wrong impression of relations with my family.”

Bardet, mayor since 1981 of the village of Ville-la-Grande – population 8,000, in the Haute Savoie near the Swiss border – said he had never discussed same-sex marriage with his son.